illustrating the Distribution of Mar hie Animals. 215 



In the Pacific the tropical currents shew their effects near 

 the coasts of New Holland and China, in a gradual diver- 

 gence of the lines from the equator. The ranges of islands 

 forming the Tarawan, Radack, and Ralick groups, appear to 

 divert the current northward in that part of the North Pa- 

 cific, and consequently the isocrymal lines bend northward 

 near longitudes 170° west and 180° ; and near Niphon that 

 of 68° shews a still greater northern flexure. 



The influence of the extra-tropical currents in this ocean 

 is remarkably great. The southern flows from the west and 

 south, bending upward the line of 56° F. along the South 

 American coast, producing at Valparaiso at times a sea-tem- 

 perature of 48° F. Still farther north it throws the line of 

 68° F. even beyond the equator and the Gallapagos ; and that 

 of 74° F. nearly 1500 miles from the coast, and 400 north of the 

 equator. The line of 62° F. reaches even beyond Payta, the 

 sea-temperature at this place being sometimes below 61°. 



The north polar current produces the same result alon'g 

 the eastern coast of Asia as on the eastern of America. The 

 isocryme of 74° F. is bent southward from the parallel of 

 23° to 12° 30' north, and that of 68° F. from 34° to 15° north ; 

 and the latter deflection is even longer than the correspond- 

 ing one in the Atlantic. The trend of the coast opens it to 

 the continued action of this current until the bend in the out- 

 line of Cochin-China, below which the cold waters have less 

 influence, although still shewing some effect upon the heat- 

 equator. The isocryme of 44° is bent southward to Niphon 

 by the same cold waters, and from this part of the Northern 

 Pacific the current appears to flow mostly between the islands 

 of Japan and the continent. 



In the Indian Ocean the effects of the tropical current, as 

 it flows westward, are apparent in the southern deflection of 

 the several isocrymes. The trend of the coast favours a con- 

 tinuation of the current directly along the coast, and conse- 

 quently its modifying influence on the sea-temperature reaches 

 almost to Cape Town on the coast, and passes even beyond 

 it at sea, crrrying 56° F. to the meridian of 15° east. 



By comparing the regions of the different oceans, north 



